We combine the labeling of newly transcribed RNAs with 5-ethynyluridine with the characterization of bound proteins. This approach, named capture of the newly transcribed RNA interactome using click chemistry (RICK), systematically captures proteins bound to a wide range of RNAs, including nascent RNAs and traditionally neglected nonpolyadenylated RNAs. RICK has identified mitotic regulators amongst other novel RNA-binding proteins with preferential affinity for nonpolyadenylated RNAs, revealed a link between metabolic enzymes/factors and nascent RNAs, and expanded the known RNA-bound proteome of mouse embryonic stem cells. RICK will facilitate an in-depth interrogation of the total RNA-bound proteome in different cells and systems.

No abstract

Heterotaxy, a birth defect involving left-right patterning defects, and primary ciliary dyskinesia (PCD), a sinopulmonary disease with dyskinetic/immotile cilia in the airway are seemingly disparate diseases. However, they have an overlapping genetic etiology involving mutations in cilia genes, a reflection of the common requirement for motile cilia in left-right patterning and airway clearance. While PCD is a monogenic recessive disorder, heterotaxy has a more complex, largely non-monogenic etiology. In this study, we show mutations in the novel dynein gene DNAH6 can cause heterotaxy and ciliary dysfunction similar to PCD. We provide the first evidence that trans-heterozygous interactions between DNAH6 and other PCD genes potentially can cause heterotaxy. DNAH6 was initially identified as a candidate heterotaxy/PCD gene by filtering exome-sequencing data from 25 heterotaxy patients stratified by whether they have airway motile cilia defects. dnah6 morpholino knockdown in zebrafish disrupted motile cilia in Kupffer’s vesicle required for left-right patterning and caused heterotaxy with abnormal cardiac/gut looping. Similarly DNAH6 shRNA knockdown disrupted motile cilia in human and mouse respiratory epithelia. Notably a heterotaxy patient harboring heterozygous DNAH6 mutation was identified to also carry a rare heterozygous PCD-causing DNAI1 mutation, suggesting a DNAH6/DNAI1 trans-heterozygous interaction. Furthermore, sequencing of 149 additional heterotaxy patients showed 5 of 6 patients with heterozygous DNAH6 mutations also had heterozygous mutations in DNAH5 or other PCD genes. We functionally assayed for DNAH6/DNAH5 and DNAH6/DNAI1 trans-heterozygous interactions using subthreshold double-morpholino knockdown in zebrafish and showed this caused heterotaxy. Similarly, subthreshold siRNA knockdown of Dnah6 in heterozygous Dnah5 or Dnai1 mutant mouse respiratory epithelia disrupted motile cilia function. Together, these findings support an oligogenic disease model with broad relevance for further interrogating the genetic etiology of human ciliopathies.

Synthesizing solid solutions of IrO 2 via doping is known to be a viable approach for effectively using iridium metal by enhancing its intrinsic properties. However, such composites at certain fractional values of dopants realize the substitution limit because of lattice mismatch. Here, on the basis of density functional theory studies and experimentation, we demonstrate codoping as an effective approach to overcome this result with an outstanding oxygen evolution reaction (OER) activity. Nickel and cobalt as the case dopants for the host structure IrO 2 atomically substituted 50% of the precious metal. As a new structural insight, the decreased crystal energy was determined to be the key factor for considerable insertion of dopants. Furthermore, the synthesized codoped IrO 2 reflected an overpotential of only 285 mV at a current density of 10 mA•cm −2 , which is appreciably lower than the 320 and 330 mV for individually doping cobalt and nickel, respectively. Our presented approach suggests further OER optimization methods with extensive reduction of precious metals.

Minimization of noble metal contents along with enhancement in electrochemical properties with high durability is a major challenge to be overcome for commercializing water electrolyzers and cheap energy storage devices. Sluggish kinetics of the oxygen evolution reaction (OER) within the electrolytic cell and high energy demand to form OO bonds have attracted more responsiveness to this area. We report the OER beneficial mixed oxide composite of molybdenum and iridium oxides by a facile hydrothermal method. Adhered IrO 2 nanoparticles on MoO 3 large particles synergistically possessed a robust nature toward harsh acidic water electrolysis as compared to an alkaline environment. Mass specific OER activity of iridium active centers was greatly enhanced by 7-fold, twice the current density, and was attributed to electronic modulation of noble metal. Enhanced surface area and the existence of highly oxidative species in the O(1s) spectrum of IrO 2 and two doublet regions in the X-ray photoelectron spectrum of molybdenum metal were found, accountable for the robust performance. Prepared composite possessing only 30% molar fraction of noble metal presented an excellent long-term stability for 40 000 s. Reduction in the Tafel slope from 57 to 77 mV dec −1 for IM-30 and IrO 2 respectively was observed. The conducted research will open up new avenues for more applications of molybdenum oxides and their derivatives for water splitting.

No abstract

Here, we report an effective strategy to lower Ir consumption and boost the OER performance in acid by loading IrO2 onto MnO2, in which the IrO2 crystals are well dispersed and undergo a so-called z-extension Jahn-Teller distortion in the octahedral structure. Compared with IrO2, the mass activity and intrinsic activity for IrO2/MnO2 were largely increased.

Due to the great similarity to the natural extracellular matrix and minimally invasive surgeries, injectable hydrogels are appealing biomaterials in cartilage and bone tissue engineering. Nevertheless, undesirable mechanical properties and bioactivity greatly hamper their availability in clinic applications. Here, we developed an injectable nanocomposite hydrogel by in situ growth of CaP nanoparticles (ICPNs) during the free-radical polymerization of dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) matrix (PDH) for bone regeneration. The ICPNs are self-assembled by incorporation of poly-l-glutamic acid (PGA) with abundant carboxyl functional groups during the formation of carboxyl–Ca2+ coordination and further CaP precipitation. Furthermore, the carboxyl groups of PGA could interact with the tertiary amines of DMAEMA fragments and thus improve the mechanical strength of hydrogels. Upon mixing solutions of DMAEMA and HEMA bearing PGA, Ca2+, and PO4 3–, this effective and dynamic coordination led to the rapid self-assembly of CaP NPs and PDH nanocomposite hydrogels (PDH/mICPN). The obtained optimal nanocomposite hydrogels exhibited suitable injectable time, an enhanced tensile strength of 321.1 kPa, and a fracture energy of 29.0 kJ/m2 and dramatically facilitated cell adhesion and upregulated osteodifferentiation compared to hydrogels prepared by blending ex situ prefabricated CaP NPs. In vivo experiments confirmed the promoted osteogenesis, which shows a striking contrast to pure PDH hydrogels. Additionally, the methacrylate groups on the monomers could easily be functionalized with aptamers and thereby facilitate recognition and capturing of bone marrow stromal cells both in vitro and in vivo and strengthen the bone regeneration. We believe that our conducted research about in situ self-assembled CaP nanoparticle-coordinated hydrogels will open a new avenue for bone regeneration in the future endeavors.